The Reality of the Biggest Loser is on Netflix, find out why host Alison Sweeney left the show and what she does now.

Netflix's tell-all docuseries about 'The Biggest Loser' featured interviews with former contestants, trainer Bob Harper and more — but not Jillian Michaels

For those less familiar, let's take a look at who Jillian Michaels is and what she's been up to since the Biggest Loser wrapped – and what we know so far about her decision not to appear in the Netflix docuseries,

Mockery, dangerous weight loss practices and long-term health impacts — “The Biggest Loser” was a TV phenomenon that shaped how Americans view weight.

Michaels was a trainer on “The Biggest Loser” for seasons 1, 2, 4-11, 14, and 15. She often motivated contestants by yelling at them or insulting them. In one clip from “Fit for TV: The Reality of the Biggest Loser,” Michaels pushes a woman to keep exercising even after she vomits on a treadmill.

Rachel Frederickson won The Biggest Loser Season 15 in 2014 after losing a staggering 155 pounds, dropping from 260 pounds to just 105, meaning she’d shed nearly 60% of her body weight over the course of the competition. When she stepped on stage at the finale, viewers, fellow contestants, and even the show’s trainers appeared visibly stunned.

Although Michaels was not featured in the docuseries, she has spoken openly about her time on The Biggest Loser and her life since leaving the hit show. Michaels has continued working in the health and fitness world while getting involved in podcasting and politics, including meeting with the Trump administration.

Tracey Yukich tells Fox News Digital that she learned a lot about herself on the show. Yukich appears in the new Netflix documentary "Fit for TV: The Reality of the Biggest Loser."

"The temptation challenges were the hardest part of the show for me," Sweeney says in Netflix's docuseries, 'Fit for TV: The Reality of The Biggest Loser'